The invention relates generally to marine propulsion water pumps past, such water pumps have included a single impeller and a series of flow-straightening vanes which were fixed in the water passage or tunnel rearwardly of the impeller and which served to straighten the rearwardly directed water flow. However, while these vanes did serve to straighten water flow and to increase flow velocity, the vanes also impeded water flow due to drag induced by water flow therepast.
Attention is directed to the following U. S. Pat. Nos.:
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